You don't have to reach Olympic standards or beat your fourteen-year-old daughter running down the street. You don't have to progress week by week so that your standard visibly improves, just as you don't have to play to win. You are not competing against anyone else you are exercising to improve your muscle tone, to become stronger and more supple, to balance your calorie intake, to improve your heart and ling efficiency, and to become a healthier person, so you can set your own standards. The important thing is to find a routine which you will enjoy enough to follow regularly.
Exercise is not only for the already fit; invalids or the disabled should not feel excluded and often those with bad backs, heart complaints or nervous disorders, or those who are over-weight or pregnant, are the very people who need exercise most. However, if you suffer from any illness, disability, back or heart problem, always see a doctor before taking up exercise. You should also consult your doctor if you haven't undertaken any sport or exercise for more than five years.
While the help of your doctor and the suggestions here are overleaf, you should be able to find a form of exercise which will suit your lifestyle. An exercise or dance class, for example, or a regular daily exercise routine, will help to improve your posture and strengthen your back, but if you have a weak back you obviously shouldn't go in for weight lifting.
Most doctors now agree that regular monitored exercise is the best way to countering heart disease. Heart patients are no longer treated as more delicate than lilies. Of course, exercise must be done under medical supervision, taking it easy at first and gradually building up strength, remembering that while the correct exercise will benefit a weak heart, inappropriate exercise may damage even the most healthy one.